This invention relates to a method for the fabrication of full or partial dental restorations, including veneers, crowns, inlays, onlays, and bridge structures, hereinafter referred to as dental restorations.
The invention utilises the technique of flame spraying to produce a relatively dense basal layer of a technical ceramic based material which firstly acts a permanent form upon which porcelain can be applied in order to yield ultimate aesthetics of the restoration, and which secondly serves to strengthen the restoration and provide a means for bonding the restoration to a prepared tooth in which the contribution made by the mechanical bonding mechanism is enhanced.
According to the present invention there is provided a method for the manufacture of a dental restoration including the steps of forming a model of refractory material of a tooth, and forming, by flame spraying directly on to said refractory model, a base layer of technical ceramic based material of a predetermined thickness of said restoration, said refractory model being of high thermal conductivity and cooled during the formation of said base layer.
The method may include the further step of firstly subjecting the refractory model to burn out and optionally a hardening heat treatment at temperatures in the range of 1000-1150xc2x0 C.
The method may include the addition of silicate based material into the precursor powder or after the formation of the base layer.
The method may include the further step of sintering said base layer of technical ceramic based material and applying to said base layer one or more layers of dental porcelain.
The method may include the additional step of removing the refractory model immediately after forming said base layer and prior to the sintering and application of said layer(s) of dental porcelain, or alternatively removing the refractory model after the sintering stage but prior to the application of said dental porcelains.
Preferably, the refractory model will be formed by casting in a silicone based impression of said tooth.